The strong desire, and increased effort, to prevent an “invasion” of non-native quagga mussels, or their zebra mussel kin, into the Pacific Northwest’s waterways has shown benefits over the past weeks or two, and more, due to diligence.

The Idaho Department of Agriculture’s Invasive Species Program manager, Amy Ferriter, offered “kudos to our inspectors for looking at” barges that did not at first blush look like boats that might have become encrusted with the tiny but highly productive mollusks.

Quaggas, which first landed on U.S. soil in the 1980s in the Midwest-Great Lakes Region, are native to eastern Europe. They have since found their way west, most notably to Arizona’s Lake Mead and other Southwest reservoirs. In the Midwest, their rapid growth, and affectation for metal and concrete structures that make up water transmission infrastructure, has served to clog the works and cause millions of dollars of remedial action.

Lake Mead and other infested areas in the region, including Southern California, have suffered the same quagga affliction, but the water sensitive Northwest has yet to be invaded. Battle plans have been drawn, as boat traffic from the Midwest and Southwest is common, and recreational craft are among of the most common distributors of the invasive mussel species.

Idaho has established check stations long its borders with Montana, Washington and Nevada specifically to corral infested boats. Two recreational craft alone were identified last week as being infested with quagga mussels, both headed from Lake Mead to Canada.

The Idaho interceptions include 25 “fouled” boats identified this year, including 13 interceptions of barges that had been used over the past two years as floating construction stations for a Lake Mead water transmission tunneling project. The barges were being transported via semi truck to a base of operations in Seattle.

“The owners knew they needed to be decontaminated,” said Karen Vargas, a wildlife staff specialist in the Nevada Department of Wildlife’s Aquatic Invasive Species Program. The barges have been permitted by the state for use at Lake Mead since 2006.

“We weren’t even aware that they were leaving,” Vargas said of the Idaho border interceptions. “But Idaho let us know they were coming through.”

A total of 13 of the 41 barges scheduled for transport to Seattle were put under “custodial seizure” over the past weekend for further inspection. As of early this week, a couple had appeared at the Idaho border and were judged to be “clean,” Ferriter said.

Transported barges were also identified at the California-Oregon border.

Apparently, the company, Vegas Tunnel Construction, made an effort to decontaminate the vessels before beginning transport.

But “some appeared less clean than others,” said Sgt. Carl Klein of the Washington Department of Fish and Wildlife’s Aquatic Invasive Species enforcement program. Idaho and officials from other Northwest states have in recent years worked to coordinate efforts to head off invasive species invasions.

“They said they were hot-washed down there but we found a lot of mussel material on them,” Ferriter said of the border inspections.

The quagga and zebra mussels can in many cases settle into “pockets and crevices” and not be easy to spot, Klein said.

“This was a little bit different circumstances” in that the company seemed to make a good-faith effort to decontaminate the barges, Klein said.